Improving Conversation Quality for VoIP Through Block Erasure Coding

TL;DR

This paper analyzes how block erasure coding impacts VoIP quality, considering packet loss, delay, and burstiness, and finds optimal conditions for its benefits using a new analytical model.

Contribution

It introduces a novel analytical model to evaluate the effects of block erasure coding on VoIP performance, accounting for delay and burstiness.

Findings

Block erasure coding benefits are reduced by delays and burstiness.

Small block sizes and optimized buffers enhance coding benefits.

Net positive effect persists over a range of network loss rates.

Abstract

The conversational quality of voice over IP (VoIP) depends on packet-loss rates, burstiness of packet loss, and delays (or latencies). The benefits for conversational voice quality of erasure coding attributable to its reduction in packet loss rates are widely appreciated. When block erasure coding is used, our analysis shows how those benefits are reduced or even eliminated by increases in delays and in a measure of burstiness of packet loss. We nevertheless show that the net effect of those three factors is still positive over a wide range of network loss rates provided that block sizes are sufficiently small and the sizes of decoding buffers have been optimized for real-time media. To perform this analysis, we develop a new analytical model describing the effects of block erasure coding on end-to-end network performance.